Method and device for opening a flexible pouch

ABSTRACT

A method for opening a flexible pouch ( 1 ), and in particular heat-sensitive edges ( 3 ) of a mouth of the pouch, provides for the opening of the edges ( 3 ) of the mouth to occur by simple heating until the mutual detachment of the edges ( 3 ) of the opening with the formation of an adequate ( 6 ). A device for opening the pouch ( 1 ) comprises heating means so shaped as to heat a heat-sensitive area of the mouth of the pouch until causing its opening. The heating means can comprise at least a nozzle ( 7 ) able to emit a jet of warm air that heats the mouth of the pouch ( 1 ) or a pair of heated shaped guides ( 4 ) between which transits the area of the mouth of the of the pouch ( 1 ) whilst the guides ( 4 ) press against the pouch itself or are simply in contact therewith.

TECHNICAL FIELD AND BACKGROUND ART

The present invention relates to a method and a device for opening aflexible pouch, preferably made of a multilayer film ofpolyethylene/aluminium/polyethylene or polyethylene/polyethylene withdifferent molecular weight, and normally destined to contain liquid foodproducts such as juices and drinks.

The pouch is provided with a mouth/stopper made of rigid plasticmaterial, called spout, which must be applied to the pouch and sealedthereto, for instance by means of heat sealing or ultrasound sealing orhigh frequency sealing.

Said mouth or spout is used when filling the pouch with the foodproduct, because usually then the user consumes the product through astraw that is inserted into the pouch by penetrating an appropriatemembrane or weakened area of the pouch itself.

Currently, to open the pouch and introduce the spout therein, quitecomplex machines exist which perform complex motions.

Pincers are used with suction cups that slightly open the upper edges ofthe pouch while holding the pouch; a tube is then introduced, the pouchis closed around the tube, air is blown into the pouch until it issufficiently inflated, and lastly the spout is introduced and sealed tothe pouch.

One of the most critical and complex steps in the aforesaid method isthe initial one of opening the mouth of the pouch, whose edges aremutually attached without any cleft.

DISCLOSURE OF INVENTION

The aim of the present invention is to eliminate the aforesaiddrawbacks, making available a method and a device that allow easily andrapidly to open the pouch within the context of an economicalembodiment.

Said aims are fully achieved by the method and by the device of thepresent invention, which are characterised by the contents of the claimsset out below.

In particular, the method provides for the opening of the edges of thespout of the pouch to take place by simple heating, and the heating steppreferably lasts until the edges are detached and an adequate cleft isformed.

The device comprises heating means so conformed as to heat aheat-sensitive area of the mouth of the pouch until causing its opening.

The heating means can comprise at least a nozzle emitter of a jet of hotair which heats the mouth of the pouch until causing the detachment ofthe edges of the mouth, or they can comprise a pair of heated shapedguides between which transits the are of the mouth of the pouch whilstthe guides press against the pouch itself or are simply in contacttherewith.

BEST MODE FOR CARRYING OUT THE INVENTION

This and other characteristics shall become more readily apparent fromthe following description of a preferred embodiment illustrated, purelyby way of non limiting example, in the accompanying drawing tables, inwhich:

FIG. 1 shows a front view of the pouch;

FIGS. 2, 3, 4 and 4 a respectively show a front view, a plan view and alateral view and an enlargement of the pouch during the edge heatingstep;

FIGS. 5 and 6 respectively show a front and a plan view of the pouch ina step that can be the edge heating step according to an embodimentvariation or can be a subsequent step to the one illustrated in FIG. 2;

FIGS. 7 and 8 show two subsequent steps of the method.

With reference to the figures, the number 1 globally indicates aflexible pouch, in particular for liquid food product, which is made ofheat-sensitive material.

In the specific case the superposed sheets, preventively joined on threesides of the pouch are multilayer sheets of thepolyethylene-aluminium-polyethylene type or of the type constituted bytwo layers of polyethylene with different molecular weight.

In particular, the inner layer of each sheet has a lower melting pointthan that of the outer layer and the thermal expansion coefficients ofthe inner and of the outer layer are different. The reason for thisshall be clarified in the course of the description.

The pouch, whose upper edges 3 in the mouth area are substantiallyattached to each other without any cleft, is held in known fashion bypliers schematically indicated as 2.

To detach the edges 3 and to create an adequate cleft that allows thepreliminary inflation of the pouch before the step of filling with theproduct, originally heating means are applied constituted by a pair ofshaped guides 4 between which transits the pouch supported by thepliers, in the direction indicated by an arrow 5.

The guides 4 preferably have the shape of two cylindrical bars withcircular cross section and are kept heated by appropriate means (forinstance electrical resistors or internal circulation of steam) not showherein at a temperature of about 100° C.

The fact that the sheets constituting the pouch are of the multilayertype with the inner layer having a different thermal expansioncoefficient from that of the layer constituting the exterior of thepouch, produces a separation of the edges 3 as a result of the heatingoperated by the guides 4, creating a cleft 6.

In a subsequent step, illustrated in FIGS. 5 and 6, through said cleftis blown air that produces the inflation of the pouch (shown in FIG. 6).The air, which preferably is sterile, is introduced through a nozzle 7that blows coaxially on the pouch from above, but it can also beintroduced through multiple nozzles blowing in different directions.

The Applicant has also surprisingly discovered that if warm air is usedto inflate the pouch, and in particular air at the temperature of about50° C., said flow of air is in itself sufficient both to detach theedges of the mouth and to achieve the subsequent inflation of the pouchand therefore, according to this, even simpler, embodiment variation,the heating of the mouth with the guides can be eliminated.

Once the edges 3 are separated, the mouth of the pouch must be fullyopen: to do so, one or more jets of sterile air can be used (as shown inFIG. 5), or a blade 9 or stainless steel element can be employed, whichpartially penetrates into the pouch as shown in FIG. 7, or one can beaided by suction cups that are attached to the lateral walls of thepouch, distancing them.

Thereafter, the pouch is inflated with sterile air, receives the spoutin known fashion and the edges of the mouth are sealed to each other andaround the spout. The fact that the melting point of the inner materialis lower than that of the outer material allows to heat seal the partsthat face internally to the pouch, preventing the outer parts frommelting and becoming attached for example to the sealing bars or pliers.

Once the spout is readied, the pouch is filled according to a knowntechnique.

The pouch can comprise a weakened area or a membrane 8 through which theuser can introduce a straw to consume the content of the pouch.

In the specific case, the method and the device have been described forthe opening of a flexible pouch provided with filling spout and destinedto contain drinks, but they can be applied, without departing from thescope of protection of the invention, also to other types of pouches,with or without spout, destined to contain other types of products, inliquid, solid or powdered form.

In fact, neither the shape of the pouch nor the product it is to containare essential, but only the material whereof the pouch is made, whichmust be such that the edges of the mouth of the pouch react positivelyto a heat source by widening and distancing from each other, forming acleft.

1. Method for opening a flexible pouch (1), and in particularheat-sensitive edges (3) of a mouth of the pouch, characterised in thatit the opening of the edges (3) of the mouth occurs by simple heating.2. Method as claimed in claim 1, wherein the heating step lasts untilthe mutual detachment of the edges (3) of the opening with the formationof an adequate cleft (6).
 3. Method as claimed in claim 1, wherein theheating is achieved by blowing warm air at a temperature of about 50° C.4. Device for opening a flexible pouch (1), characterised in that itcomprises heating means so shaped as to heat a heat-sensitive area ofthe mouth of the pouch until causing the opening thereof.
 5. Device asclaimed in claim 4, wherein the heating means comprise at least a nozzle(7) emitting a jet of warm air that heats the mouth of the pouch (1)until causing the detachment of the edges (3) of the mouth and thedefinition of an adequate cleft (6).
 6. Device as claimed in claim 5,wherein the warm air is at a temperature of about 50° C.
 7. Device asclaimed in claim 4, wherein the heating means comprise a pair of heatedshaped guides (4) between which transits the mouth area of the pouch (1)whilst the guides (4) press against the pouch itself or are simply incontact therewith.
 8. Device as claimed in claim 7, wherein said shapedguides (4) have circular cross section and are therefore cylindricalbars.
 9. Flexible pouch for food products, characterised in that it isopened by means of a method as claimed in claims 1 through 3 or by meansof a device as claimed in claims 4 through 8.